Cold process transfer coating



Patented May 27, 1952 OFFICE COLD PROCESS TRANSFER COATING COMPOSITIONS George Walton, Cincinnati, Ohio No Drawing. Application November 29, 1948, Serial No. 62,591

This invention relates to cold process transfer coating compositions for paper or similar base material, and has to do more particularly with a cold process transfer spot coating composition which is applied. to a selected area or areas on the reverse or rear side of the paper or other base for reproducing marks or characters which are to be typed or written on the face orfront side of the paper.

Transfer coating compositions which, heretofore, have been generally used are thermoplastic, and heated to a molten condition before being applied as a coating, or, are rendered liquid by the useof a solvent for application and then set or dried by vaporizing the solvent. Thermoplastic transfer coating compositions require heaters for liquifying them immediately before their application as a coating, and, also require cooling devices to set the coating as quickly as possible after it is applied. Those coating compositions which are 'liquiiied, in commercial practice, by a solvent require heaters to evaporate the solvent immediately after the coating has been applied so that the coated sheets may be superimposed without ofi'set.

In practice, transfer spot coatings are printed on selected areas of a paper base. With both the thermoplastic and solvent activated types of coating compositions, the special heaters, and in some cases coolers, must be attached to th printing machine, for unless the coating is promptly set between printing operations of the machine, itwill offset onto the .face'or front side of the next printed sheet. Thus in both of these methods special apparatus isrequired, and much control needs to be exercised in having the coating composition applied under proper conditionsflf It will, also, be appreciated that obnoxious fumes andodors are given oil in both of the above methods, andthat they areo'bjectionable anddisagreeable for working" conditions as well as beingfire hazards. f Some transfer compositions have been compounde'dfor spot transfer coating without the use of special heating or cooling apparatus. However, such compositions. have not proved satisfactory because they are either too hard or'too soft. ".'Ihose which are too hard do not spread well as a coating and do not transfer well after being applied. Those whichare too 's'oftdo not set to a non-fiuidcon'dition, and thereby penetrate the paper unduly and are'subject to offset that causesv smudging or smearing of the uncoated side of the sheet when a number of sheets are superimposed in being handled and stacked. Eventhe thermoplastic or heat liquified coating 4 Claims. (01. 106-31) compositions and those liquified by solvents, are not entirely free from these objections sinc they require careful control in bein applied to the sheet and dried. However, the hot process compositions have been the least objectionable, and,

,, therefore, have been used more generally even though requiring special apparatus for their application to the paper.

A principal object of the invention is to provide a transfer coating composition which can 7 be spread in a film coating with conventional coating apparatus and which will set, without special treatment, sufiiciently rapidly to avoid smudge or oifset. More specifically, an object of the invention is to provide a cold process transfer coating composition which, at normal room temperatures, is in solid form and resistant to free flow but sufiiciently soft to be spread in a film layer, and readily becomes free flowing under the mechanical manipulation to which it is subjected in being applied as a transfer coating on paper.

Another object of the invention is to provide a normally solid cold process transfer coating composition which is changed to a liquid by the mechanical manipulation to which it is subjected in being applied to the paper as a, film coating, and will revert to its normal solid form and be resistant to free flow when not disturbed by mechanical manipulation. v

Another object of the invention is to provide a cold process transfer coating composition which is adhesive to the paper but does not unduly penetrate the same.

Another object of the invention is to provide a cold process transfer coating composition which sets to either a thixotropic gel or solid solution and does not objectionally penetrate the paper base to which said coating is applied.

the compositions in the coating operation.

' Further objects, and objects relating to details of the composition and application of the composition as a transfer coating, will definitely appear from the detail description of the invention.

My invention comprises a cold process transfer composition 7 which needs'no special apparatus for-"its. application as a coating. It-is normally solid and resistant to free flowing although suffinciude those designated in ficiently soft to be readily and evenly spread, is free flowing under ordinary conditions of being applied as a coating to paper, is adherent to but does not unduly penetrate the paper, and subsequently reverts to a solid condition, following application as a coating, so as not to offset or smear. It is normally, at ambient temperatures from to C., in solid form but soft enough to be readily spread in a thin coating. The coating composition is normally a soft thixotropic gel or solid solution and is not free flowing. -While there may be a distinction between a thixotropicgel and a solid solution, the diiference isnot easily ascertainable where one of the components is a liquid. Thus the term thixotropic gel will be used broadly in reference to the novel composition here disclosed and without regard to any distinction between it and a solid solution. It refers to a composition having thecharacter of being solid when not disturbed bymecha'nical manipulation andllquid when 'so disturbed. By a thlxo'ti'opic "gel, I mean a composition which exists as a gel but changes to a liquid state (free flowing under the influence of gravity) upon mechanical manipulation, -such as stirring, shaking or compressing. It reverts to a solid gel when at rest and not subjected to mechanical manipulation. A "gel is a semi-rigid mass consisting of two or more phases, one of Which fsaliquid, to'pfoduce a mass which maintams a definite shape against the pull of 1 A transfer composition embodyingmy invention comprises a non-dryingliquid oil, a solidwax and 'a pigr'nent and/or dye, these being combined in such proportions that the compositionis normally 'a thixotropic gel or solid solution which is soft and spreadable but not free flowing. The proportions of the oiland wax vary, depending of the oil. However, the ratio or the n to the wax for obtaining a composition of novel character can be determined the hereinafter described formula which correlates the proportions of the oil andwax relation to the melting point'of the wax and the viscosity of the oil. The oil comprises about i8 to 80%, by weight, of the composition, and preferably from about to 70%. 1

Ihe oil isfpreferably of the type obtained in refining crude petroleum and is that fraction within a distillate range, generally known and 'referred to as cylinder stock or lubrication oil. The lubrication oil is the heavy distillate the range between fuel oil and petroleum grease, the latter being a semi-solid combination petroleum productand'a soap, 'o'ra mixture of soaps. Lubrication oars include those which-are indicated as of high, mediuinand lowfyiscosity, and ordinarily are refined to remove'sludge therefrom. I I

. other liquid non-drying oils, suon'as vegetable oils and animalfoils are also suitable. The oils the trade by their 1s. A. visoo ity, mogmg from '10 to 250, n

those lighter lidu'id oils which have 'a viscosity upon the hardness of the wax and the viscosity and not less than 10 but whose viscosity is not designated in the trade. These lighter oils are spindle oils and the like, and are generally designated and classified in the trade under names which do not specify the viscosity of the oil. However, such oils are suitable, and theirviscosities can beasoertained for determining the'proper proportion to be used with the wax component in the present invention. Oils above a viscosity of S. A. E. No. 250 are too hard and stiff to provide a composition which can be rendered free flowing and, therefore, are not suitable in the present invention, A larger proportion of wax or one of harder character is required for lighter oil or oil or lower viscosity, whereas a smaller proportion o'f wax or one of softer character is'required for heavier oils or oils having a higher viscosity. It is essential that the oil be liquid, and liquid oil of any viscosity is suitable if same is non-drying. The oil should be non-drying and one which is and remains liquid and free flowing without channeling at normal temperatures from 15 to 35 C. Those oils, such as linseed oil, and the like, which oxidize and irreversibly set" by chemical action to solids or semi-solids are not suitable for the oil component in the composition embodying the present invention, but may be added in small quantities with the non-dryin oil without impairing the character of the composition. I I

The wax may be any of the natural solid waxes such 'as 'spermacetti, parafiin, yellow or white beeswax, carna'uba, montan and the like. Synthetic waxes are also suitable where they approximate substantially the natural waxes by a mix-- ture of their principal components. All synthetic waxes do not, however, duplicate or even approximate the components of the natural waxes, and thus their suitability in the present invention dependent upon their approximation with the principal components of the natural waxes.

Liquid waxes are not suitable alone in the invention, but a small proportion of liquid'wax may be advantageously included with the solid wax to improve the quality of the oil and wax transfer coating composition inbeing 'm'echa'r'iic'ally drawn out into thin strands or threads. This 'qualit'yfof a transfer coating composition is referred to in the art as fiber length, and this quality 'of having fiber length or capability of being drawn out into thin strands of threads is necessary for thesuccess'ful feeding of the coatinf'g composition through a Series 'of rollers '01 other mechanisms which carry same to the "forms for its transfer "to the surface or surfaces to be fsp'ot printed, Inclusion of a small quantity of liquid wax, with the solid wax, is advantageous where the solid wax is of the harder kind, so that the quality of fiber length of the composition isnot impaired. I I I The concentration of the oil and wax components in the composition issuch that the is partially and incompletely dissolved in the oil, and is dispersed therein with theoil forming one phase and the wax forming the other phase of the dispersion. The wax and the oil form either a thixotropic gel or solid solution which is normally sufficiently soft to be easily spread in a film coating but is not free flowing, anddoes not offset and smear undernormal conditions. The coinpositionhas the character of a solid'whenat rest I I disturbed by mechanical manipulation, whereas it has the character of aliquid when :dis- 'turbed by mechanical 'inanipulation. Otherwise .toners and the like.

combined proportions of the wax and coloring material. but with oils of low viscosity, the wax component may exceed that of the oil.

The coloring material may be one which is or is not in solution in the composition, or a combination of the two types. The coloring material is preferably wholly or mainly a solid pigment which is. not in solution in the composition as it gives more body to the composition and functions .to' makesame more resistant to penetration in thepaper. The solid pigment is filtered out of any part of the vehicle which tends to penetrate the paper, whereas coloring material which is in solution has a tendency to follow any portion of oil which penetrates the paper. This is commonly referred to as bleeding. Any coloring pigment may be used. Where the coloring material, such as a dyestufi, is of a type to be in solution in the composition, some finely divided inert solid insoluble filler is preferably included, even though such filler may be colorless and not a pigment. Diatomaceous earth, bentonite, talc and the like are suitable for this purpose. Such inert fillers help to localize the coating on the .surface of the paper and prevent bleeding of the dye into the paper. Conventional pigments may be used for the'coloring material, such as carbon black, lampblack, metal oxides, lakes, Carbon black is preferred as it is ordinarily, more finely divided and-therefore, a smaller amount can be used for obtaining proper pigmentation. Where a soluble dyestufi is used, a suitable acid, such as oleic acid or the like, is included in sufficient amount to dissolve the dyestuff and disperse same through the composition. The coloring material is not necessarily of the kind that renders the transfer composition visible to the naked eye, and may be one which is ordinarily considered colorless but is fluorescent, and thereby renders the composition fluorescent so that it will glow under ultra-violet light and be visible. .Thus the term coloring material is used-broadly to refer to a .dyestuff. pigment or the like, irrespective of .whether or not the material may, of itself, be colored or colorless. r

If soluble coloring material be alone'used, same may range from 1 to by weight, depending upon the type of the dye. A solid pigmentis used in proportion, by weight, up to about 45%, preferably about 15 to if used alone. Enough pigment should be included to give the desired density of color or pigmentation to the composition, and this can ordinarily be obtained with about 15 to 35% of solid pigment. It is desirable to use the least amount of coloring material which is necessary for proper pigmentation. An amount of solid pigment in excess of renders the composition too thickfor spreading, and impairs its characteristic of being rendered liquid by mechanical manipulation. Where both soluble and insoluble coloring materials are usedin the composition, they may be in any proportion in respect to each other, and their combined amounts will be in any proportion not in excess of 45%, and preferably not in excess of 35%.;

The amount of insoluble coloring material is decreased as the amount'of solublecoloring matter is increased. The amount of solid coloring material useddepends also on its fineness. With equal amounts. by weight, of two or more solid coloring materials, that which is more finely divided will present a greater surface area or areas to be covered by the oil and wax vehicle, and thus will be more effective than coarser material in coloring the composition. Accordingly, a less proportion of more finely divided solid material can be used,

other things bein the same, andbe as effective as a larger proportion of coarser material. Carhan black, for example, is ordinarily more finely divided than any of :the otherv above mentioned solid colored materials, and therefore, is preferred as less of it need be used.

Some preferred specific examples, embodying my invention, are given below, these including transfer compositions with solid pigments, soluble pigments, or a mixture of the two:

Solid pigments Per cent 1. Pale yellow parafiin oil, S. A. E. 10 60 Yellow beeswax 20 Carbon black 20 2. Lard oil, S. A. E. 10 (preferablyl to 5% free fatty acids); '68.2 Yellow beeswax 11.3 Carbon blaok 20.5 3. Mineral oil, S. A. E. 50 69.9 Yellow beeswax Q. 11.1 Carbon black 19' 4. Mineral oil, S. A. E. 40 71.3 Yellow beeswax 11.2 Carbon black 17.5 5. Mineral oil, S. A. E. 40".; 60 Yellow beeswax 20 Fast violet No. 7001 (solid lake pigment) 20 6. Mineral oil, S. A. E. 250 72 Yellow beeswax Q 8 Carbon black"; 20' 7. Mineral oil, S. A. E. 60 60.5 Yellow beeswax 8.7 Lampblack 30.8 8. Mineral oil, S. A. E. No. 52.8 Anthracene (solid fluorescent pigment) 26.5 White beeswax 13.2 Flexo Wax C (synthetic wax manufactured by Glyco Products Co.) 7.5

Soluble pigments Per cent Talc (inert filler)--- 28.0

Mixed solid and soluble pigments 7 Per cent 11. Mineral-oil, S. A. E. No. 140 -1 42.3 Lampblack 28.8 Yellow beeswax 9.6

. Oleic. acid 11.5

Dye, Ciba Oil-Soluble Black, c. G-.. 7.8

components in the composition which is critical.

In the above Examples '9 and '10, the oleic acid is 'a fatty acid and may be cOllS'ideld as a 'part of the oil rractidnc'r'the liquid phase of the ve- 111018.

The foregoing 'examples are preferred compositions, embodying this invention, and are representative of those in which soluble and insoluble solid pigments are each used alone, or in combination, The proportion of pigmentprese'n't in the 'cbmposition, below a certain maximum, isnot critical in respect to the novelcharac'ter of the oil and wax vehicle, same being adapted to licensed me wide range. The only limitation that the pigment be not used, where same is insoluble, in such large proportion as to impair the spreadability of the coating composition. The soluble coloring material is more diffuse than the insoluble material and is not filtered from the portion of the vehicle which permeate the paper.

It-is for this reason that a soluble dye should be usedin a limited amount and preferably with some'inert solid filling material which would tend to prevent the co1orffrom bleeding? into the paper, Thedye would coat the particles of the inert filler. The critical factor is in the proportions of the oil and wax components in the disp'eisioi'i vehicle in which the coloring matter is "dispersed. The proportions of moon and wax should be within definite limits, depending upon the melting point of the wax and the. viscosity of 'the' oil, to provide a normally soft, spreadable thixotropic gel or solid solution that is normally resistant to free new but is free fiowing when subjected to mechanical manipulation. The dispeision has the liquid oil and solid wax phases so'pi'opo'rti'oned or balanced that'the composition'nor'mally, when at rest, is caused by the wax to'be solid, and when disturbed is caused by the on to be liquid. V V

While more or less oil may be used in the composition, the solid wax is combined such prop ltion that it is partially and 'inccmpieteiy dissolved in the oil, and su'fficicntly dominates or influorides the physical character of the composition under certain conditions'thereby causing the dispersion normally to set to a thixotropic gel or solid solution and be resistant to free flow.

However, when thecompo's'ition is subjected to mechanical manipulation, such as pressure, stirring and squeezing, by and between the applica- "tor, fountain, or form rolls, and by and between said rolls and the paper being coated in the coating operation, the oil dominatesorinfiuences the physical character of the compositionso that it is rendered liquid and free flowing without the use of any other means. Following the coating operation and the cessation or release of the mechanical manipulation cfuthe coating operation, the coating sets to a relatively soft, solid condition and does not offset or smear.

From the foregoing description, it is apparent that a cold process coating composition embodying my invention is not only well suited for transfer but is normally solid to be resistant to offset and smear before being used for transfer. It also has better aging qualities due to minimum absorption of the vehicle by the paper.- Moreover,

in being applied as a transfer coating, the comhaving 'a coloring matter dispersed. therein, the

on having a viscosity not in excess of 250 com"- prising about 48 to 80% of the omposition, by ht, and the was "comprising "about '2 to 35%, eight, "of the composition, 'sa'id composition ally being in the form ofa spreadable-thixo'- tropic ge1 in which the wax is incompletely solved in the 611, and which is resistant to free flowing at ordinary room temperatures or about 210th 35 C. but is capable of beecrhirig-rree flowi'ng when subjected to mechanical mathematics and of r verting to said soft, solid "gel tree from mechanical manipulation.

A cold process transfer coating ee msiuoh comprising a SOlfd waxand 'ribn dry-ingoil havin acolor'ing'matter'dispersed therein; thc'o'il having a 'viscos'ity not in excess of 250 comprising about 48 to 80%, by weight, of the composition and the wax comprisin about 7 to 25%, by Weight, of the composition, said composition normally being in the form (if a Soft, s'prea'dable thiXotldplC 861 iii which the wax is incompletely dissolved the oil, "and which is resistant to free flowing a'to'idi nary room temperatures of about 20 to '35" C. but is capable of becoming free flowing when sub jdtd to mechanical manipuiation'and reverting to "said soft, solid gel when releases 'from'mee' cha'n'ical manipulation I -3. Acold process transfer coating composition comprising a solid was and 'non drying liquid oil, 'liaving a coloring in'atte'r dispersed therein, the oil ha'ving a viscosity not in excess of 250 com-prising about '50 to 70% of the composition, by iweight, and the wax comprising about 2' to 31f) by weight, of 'the compos'iti'on, said compo sition normally being in the form of aspreadadale thixotropicgel in which the wax 'isihcompletely dissolvedin the oil, andwhich is resistant to free flowing at ordinary room temperatures of about 20 to 35 C. but is capableof becoming free flowing when subjected to mechanical manipulation-and of reverting to said soft, solid-gel when fr'ee from mechanical manipulation;

'4. cold process transfer coating composition comprising a solid wax and non-drying liquid oil; having a coloring matter dispersed therein, the oil having a viscosity not in excess of 250 comprising about 50 to 70% of the composition-by weight, and the wax comprising about 7 to 25%, by weight, of the composition, said composition normally being the form of a spreadable thixotropic gel in which the wax is incompletely dissolved in theoil, and which is resistanu-tofree flowing at ordinary room temperatures of about 20 to 35 C. but is capable of becom n freefldwmg when subjected to mechanical mam'pulation and of reverting to said soft, solid gel when free from mechanical manipulation.

GEORGE WALTGN,

' r mererehees tnfo'uo'wihg page) REFERENCES CITED Number The following references are of record in the file of this patent: 2:454:70)

UNITED STATES PATENTS 5 Number Name Date Number 1,082,099 Putnam Dec. 23, 1913 279,403 2,357,948 Gessler Sept. 12, 1944 307,714

Name Date Goepfert Jan. 8, 1946 Sugarman Aug. 26, 1947 Holik Nov.23, 1948 FOREIGN PATENTS Country Date Great Britain Mar. 29, 1928 Great Britain Mar. 11. 1929 

4. A COLD PROCESS TRANSFER COATING COMPOSITION COMPRISING A SOLID WAX NON-DRYING LIQUID OIL, HAVING A COLORING MATTER DISPESED THEREIN, THE OIL HAVING A VISCOSITY NOT IN EXCESS OF 250 COMPRISING ABOUT 48 TO 80% OF THE COMPOSITION, BY WEIGHT, AND THE WAX COMPRISING ABOUT 2 TO 35%, BY WEIGHT, OF THE COMPOSITION, AND COMPOSITION NORMALLY BEING IN THE FORM OF A SPREADABLE THIXOTROPIC GEL IN WHICH THE WAX IS INCOMPLETELY DISSOLVED IN THE OIL, AND WHICH IS RESISTANT TO FREE FLOWING AT ORDINARY ROOM TEMPERATURES OF ABOUT 20 TO 35% C. BUT IS CAPABLE OF BECOMING FREE FLOWING WHEN SUBJECTED TO MECHANICAL MANIPULATION AND OF REVERTING TO SAID SOFT, SOLID GEL WHEN FREE FROM MECHANICAL MANIPULATION. 